In exploring this viral model of tumor pathogenesis in the CNS, animal experiments are an essential component. Toward that end, the goal of the Experimental Animal and Tissue Culture Core of this program is to support Projects, and to develop the Syrian hamster model of glial tumors derived from the intracerebral inoculation of JCV. In this core, we will focus on four goals. These are: (1) Developing primary brain tumors in newborn hamsters following the intracerebral injection of JCV; (2) Perform MR imaging and post process data analysis of hamster tumors in vivo to define the growth of tumor during the course of studies and obtain a correlative information with the histopathological analysis of the samples. (3) Preparation and inoculation of either JCV-infected Syrian hamster derived tumor cells into the flanks of Nude mice and brains of newborn hamster, to identify their growth characteristics in the whole animal system; (4) Harvesting of CNS tumor tissues which arise in JCV T-antigen transgenic mice; and, This core activity will help to synergize and integrate the program's three major projects and the other core activities.